Gleason grading systemProstate cancer-Gleason; Adenocarcinoma prostate-Gleason; Gleason score
Prostate cancer is diagnosed after a biopsy . One or more tissue samples are taken from the prostate and examined under the microscope.
A biopsy is the removal of a small piece of tissue for laboratory examination.
The Gleason grading system refers to how abnormal your prostate cancer cells look and how likely the cancer is to advance and spread. A lower Gleason grade means that the cancer is slower growing and not aggressive.
The first step in determining the Gleason grade is to determine the Gleason score.
- When looking at cells under the microscope, the doctor assigns a number (or grade) to the prostate cancer cells between 1 and 5.
- This grade is based on how abnormal the cells appear. Grade 1 means that the cells look like normal prostate cells. Grade 5 means that the cells look very different from normal prostate cells.
- Most prostate cancers contain cells that are different grades. So the two most common grades are used.
- The Gleason score is determined by adding the two most common grades. For example, the most common grade of the cells in a tissue sample may be grade 3 cells, followed by grade 4 cells. The Gleason score for this sample would be 7.
Higher numbers indicate a faster growing cancer that is more likely to spread.
Currently the lowest score assigned to a tumor is grade 6. Scores below a 6 show normal to near- normal cells. Most cancers have a Gleason score of between 5 and 7.
Gleason Grading System
Sometimes, it can be hard to predict how well patients will do based just on their Gleason scores alone.
- For example, your tumor may be assigned a Gleason score of 7 if the two most common grades were 3 and 4.The 7 may come either from adding 3 + 4 or from adding 4 + 3.
- Overall, someone with a Gleason score of 7 that comes from adding 3 + 4 is felt to have a less aggressive cancer than someone with a Gleason score of 7 that comes from adding 4 + 3. That is because the person with a 4 + 3 =7 grade has more grade 4 cells than grade 3 cells. Grade 4 cells are more abnormal and more likely to spread than grade 3 cells.
A new 5 Grade Group System has recently been created. This system does a better job of describing how a cancer will behave and respond to treatment.
- Grade group 1: Gleason score 6 or lower (low-grade cancer)
- Grade group 2: Gleason score 3 + 4 = 7 (medium-grade cancer)
- Grade group 3: Gleason score 4 + 3 = 7 (medium-grade cancer)
- Grade group 4: Gleason score 8 (high-grade cancer)
- Grade group 5: Gleason score 9 to 10 (high-grade cancer)
A lower group indicates a better chance for successful treatment than a higher group. A higher group means that more of the cancer cells look different from normal cells. A higher group also means that it is more likely that the tumor will spread aggressively.
Grading helps you and your doctor determine your treatment options, along with:
- Stage of the cancer , which shows how much the cancer has spread
- PSA test result
- Your overall health
- Your desire to have surgery, radiation, or hormone medicines, or no treatment at all.
Epstein JI. Pathology of Prostatic Neoplasia. In: Wein AJ, Kavoussi LR, Partin AW, Peters CA, eds. Campbell-Walsh Urology . 11th ed. Philadelphia, PA: Elsevier; 2016:chap 110.
Gordetsky J, Epstein J. Grading of prostatic adenocarcinoma: current state and prognostic implications. Diagn Pathol . 2016;11:25. PMID: 26956509 www.ncbi.nlm.nih.gov/pubmed/26956509 .
Pierorazio PM, Walsh PC, Partin AW, Epstein JI. Prognostic Gleason grade grouping: data based on the modified Gleason scoring system. BJU Int . 2013 May;111(5):753-760. PMID: 23464824 www.ncbi.nlm.nih.gov/pubmed/23464824 .
Review Date: 5/3/2016
Reviewed By: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.